D'Addario Helicore Strings are multi-strand twisted steel core strings that are superb for the advanced and professional players. The small string diameter provides quick bow response. Through special manufacturing techniques, the Helicore strings have a warm, clear sound with excellent pitch stability and longevity. These strings work well on dark instruments and electric instruments. Great for all styles of music, classical, modern, jazz, and country. Available for a variety of instrument sizes and string tensions (select from dropdown menu).